Rotary bit with hammering device



May 31, 1932. J. A. zuBLlN Y ROTARY BIT WITH HAMMERING DEVICE FiledApril 28, 1930 4 Sheets-Sheet l W, M a R Z. m A my 1 A n May 31,1932.

J. A. zUBLlN ROTARY BIT WITH vHAMMERING DEVICE Filed April 28, 1950 4Sheets-Sheet 2 A 7 70K/Vf Y.

May31, 1932. J. A, zuBLlN ROTARY BIT WITH HMMERING DEVICE AFiled April28, 1930 4 Sheets-Sheet 3 May 31, 1932. J. A. zuBLlN ROTARY BITWITHHAMMERING DEVICE 4 Sheets-Sheet 4 Filed April 28, 1950 Patented May 31,1932 -UNITED STATES JOI-IN A. ZUBLIN, F LOS ANGELES, CALIFORNIA ROTARYBIT WITH HAMMERING DEVICE Application led April 28,

My invention relates to bits of the character employed in drilling wellsand relates in particular to a bit adapted to dig by a combined scrapingand pounding action.

The rotary system of well drilling to which my invention particularlyrelates employs drilling bits of three general classifications: thescraping type, which includes fish-tail bits; the roller or rollingtype, such as roller- 0 rock bits; and the combined scraping and rollingtype, such as disc bits and gyrating bits. The most used of the abovetypes of bits is the scraping type having one or more blades which aresteadily pressed against the bottom of the hole during rotation of thebit by the`V drill pipe, removing the formation by a slicing or scrapingaction. In the use of this type of bit hardness of the formation can beovercome efficiently only by placing hard metal cutting elements at thecutting edges of the bits. It is evident that the success of allscraping bits depends entirely on the hardness of the metal or metallicinserts at the cutting edges of the bit.

My present invention comprehends a well drilling` bit having a cutteradapted to strike the bottom formation of a well being drilled with ahammer-like action, the hammering effect obtained thereby producing asplitting, cracking. chipping, and crushing of the formation so that theresistance of the formation removed by a scraping operation is verymaterially reduced;

The invention also comprehends a mechanism adapted to apply energystored in the circulating mud fluid to impart blows to a verticallymovable cutter carried on a bit body suspended by means of a drill pipeWithin a Well being drilled.

lt is an object of the invention to provide a Well drilling devicehaving a chopping cutter at its lower end and a hydraulically operatedchipping mechanism situated adja cent to the chipping cutter and beingadapted for actuation by the drilling fluid or mud employed in therotary method of well drilling.

A further object of the invention is to pro- .vide a well drillingdevice includingr a body adapted to be suspended and rotated in a well1930. Serial No. 447,900.

by means of a string of drill pipe, this body having a scraping cutterthereon adapted to scrape the bottom formation of the well, a,reciprocable cutter adapted fora hammering or chopping action on thebottom of the well and a hydraulically operated device for periodicallyand forcibly bringing the reciprocable cutter into engagement with thebottom formation of the hole so as to disintegrate the formation by achopping, splitting, and crushing action which will enable its morereadily removal by the scraping cutters of the drilling device.

A further object of the invention is to provide a novel, simple andeffective hydraulically operated mechanism for accomplishing the desiredhammering action hereinabove setforth.

Further objects and advantages of the inventon will be made evident inthe following part of the specification.

Referring to the drawings which are for illustrative purposes only, AFig. 'l is a vertically sectioned schematic view.

Fig. 2 is an enlarged vertical sectional view of a preferred embodimentof my invention, this view showing the parts of the mechanism at thebeginning of a hammering stroke. f

Fig. 3 is an enlarged vertical section of the lower portion of the bitshown in'Fig. 2, this view showing the mechanism in position at the endof a hammering stroke.

Fig. 4 is a view similar to Fig. 3, but drawn to smaller scale, showingdisposal of the mechanism during-the lowering and raising of the bitswithin a well.

Fig. 5 is a bottom plan view of Fig. 3.

Fig. 6 is a cross section View on the plane represented by line 6-6 ofFig. 2.

Fig. 7 is a fragmentary vertical sectional view showing a form of myinvention having a single cutter adapted to accomplish both thehammering and the scraping operations 95 featured by my invention.

Fig. 8 is a fragmentary vertical sectional View showing an alternativeform of my mechanism which may be employed in the .100

practice of the invention.

Fig. 9 is a sectional view of an embodiment of my invention employing ahammer member which is impelled downwardly by the flow of drilling fluidand lifted b y means of a cable.

Fig. 10 is a cross section on a plane represented by the line 10-10 ofFig. 9.

Fig. 11 is a cross sectional view similar to Fig. 9 but showing a valvefor closing the passageway of the hammer member.

Fig. 12 is a cross section on a plane represented by the line 12-12 ofFig. 11.

Fig. 13 is a vertically sectioned view showing a form of my invention inwhich the hammer is raised hydraulically.

Fig. 14 is a section on a plane represented by the line 14-14 of Fig.13.

Fig. 15 is a vertically sectioned view similar` to Fig. 13 but showingan automatic valve mechanism for controlling the operation of thehydraulically actuated hammer.

Fig. 16 is a cross section on a .plane represented by the line 16 16 ofFig. 15.

Fig. 17 is an elevational view showing a means for raising and loweringa cable such as employed in the forms of my invention shown in Figs. 9,11, and 13.

For the purpose of indicating the general utility of my invention I havein Fig. 1 shown a preferred form of my drill bit 11 suspended androtated within a well 12 by means ot a string of drill pipe 13 which isoperated in accordance with standard practice by means of a rotary table14 and is suspended by a block and tackle system generally indicated at15. A mud pump 16 pumps mud under pressure through a rotary hose 17 intothe upper end of the drill pipe 13, this rotary mud or drilling fluidpassing downwardly through the drill pipe 13, and the bit 11 and beingdischarged into a hole or well 12 through suitable openings at the lowerend of the bit 11.

The preferred form of my invention disclosed in the drawings consists ofa hollow body 18 having operating mechanism therein. The hollow body -18consists essentially of an outer tube or cylindrical wall 20, thel upperend of which is threaded. as indicated at 21. so as to be screwed on tothe lower end 22 ot a drill collar 23 which forms the lower end of thestring of drill pipe 13; and the lower end of which is externallythreaded at 24 to receive a scraping cutter 25 having a plurality ofscraping blades 26 and being provided with a central bore 27 ofapproximately the same diameter as the interior ot the tube 20.Projecting downwardly from and communicating with the drilling fluidpassage 28 of the member 23 is a tubular member 30 of approximately haltthe diam,- cter of the tube 20. This tube 3() has a plurality ofopenings 31 therein through which drillingr fluid received trom thepassage 28 may enter the interior of the tube 2O` as indicated by arrows32. The lower end 33 of the tube is constricted so as to fit closelyaround an upper Valve stem 34 which projects from a valve 35. On theupper end of the upper valve stem 34 is a sleeve or nut 36 adapted toreceive the upward thrust of a spring 37 which surrounds the stem 34 andrests on the radial wall formed by the lower end 323 of the member 30.

Immediately below the valve within the tube 2O is a ram or hammer member38 having a vertical passage 40 therethrough, and packing means 41 nearits upper end7 and being diametrically reduced throughout the greaterportion ot' its lower extension so as to kform within the tube 2O anannular space 42 in which a ram spring or hammer lifting spring 43 isreceived. The spring 43 rests on an annular wall 44 which projectsupwardly from the body 45 of a reciprocable cutter mechanism 46 whichprojects within the lower end ofthe tube 20 and is retained therein byretaining means47 which may consist of a plurality of steel balls whichengage an annular groove 48 in the body 45 and an annular groove 50formed between the lower end of the tube 20 and the body portion of thecutter The body 45 has packing means 51 near its upper end and isprovided with a central opening 52 which communicates with the upper endof the body 45 and with discharge orifices at the lower end of the body45. A plurality of chopping blades 54 are formed radially on the lowerend of the chopping cutter 46. and as shown in Fig. 5 these blades 54may be three in number and may extend radially to the full diameter of acircle 55defined by the scraping blades 26 which may be also three innumber. The scraping cutter 25 has a plurality' ot radial slots ornotches .i6 through which the chopping blade 54 may extend radially asindicated in Figs. 1 and 5, these slots or notches 56 being placed inpositions intermediate the scraping blades 26.

The valve 35 has a lower conical formation 58 which extends downwardlyinto a conical counterbore 59 at the upper end ot the passage 40 of themember 38. and projecting downwardly from the conical formation 58 is alower valve stem 61 having its lower end 62 projecting slightly belowthe lower end 63 of the member 38. The chopping cutter body 45 alsoincludes an anvil 64 at its upper end and in a position to be engaged bythe lower end 62 of the lower valve stem 61 and the, lower end 63 of theram or hammer 38. The anvil 64 is provided with openings 65 throughwhich drilling luid may flow from the space above the anvil into thepassage 52 of the chopping eutter 46.

In Fig. 2 the well drilling device 11 is shown resting on the bottom 67of the well 12 and the reciprocating parts of the mechanism are shown inposition ready to start a hammer stroke of the ram or hammerv 38. Theupper end of the member 38 is shown in engagement with the valve 35 sothat the upper end of the passage is thereby closed thus preventingdrilling mud fro-m flowing through the passage 40 and causing thepressure and velocity of the drilling mud to be exerted against andapplied to the member 38 whereby to move the member 38 downwardly in thetube 2O at relatively high ve- 'locity and under great pressure. At thethe -momentum of the body of fluid which is` lower end of its downwardor hammer stroke the member 38 strikes the anvil 64 of the choppingcutter 46 and drives the cutter 46 downwardly with great force againstthe bottom 67 of the well. Just before engagement of the lower end 63 ofthe hammer 38 with the anvil 64, the lower end 62 of the lower valvestem 61 is engaged and stopped by the central portion of the anvil 64.As the hammer 38 continues to move downwardly toward engagement with theanvil 64, the upper end thereof is removed from the valve 35, thusreleasing the valve and allowing it to be moved upwardly by the spring37 into position against the lower end 33 of the member 30. The lowerend 33 of the member 30 forms a stop for limiting the upper movement ofthe valve 35 and the central portion of the anvil 64 providesa stop forlimiting the downward movement of the valve 35. In Fig. 3 the lower end63 of the member 38 is shown in engagement with the anvil 64 at thecompletion of a hammer stroke and the valve 35 is shown in a positionagainst the stop 33 into which position the valve 35 upon its releasehas been lifted by the spring 3 7 shown in Fig. 2. At this time drillingfluid flows downwardly around the lvalve 35 as indicated by arrows andpasses downwardly through the central passage 40 of the member 38,pressure against the upper and lower ends of the member 38being'equalized to such an extent that the member 38 may be movedupwardly by the lifting spring 43. Under upward pressure of the spring43 the member 38 then moves from its position of Fig. 3 toward the valve35. or toward the position in which it is shown in Fig. 2. During thisupward movement of the member 38 the drilling fluid is flowingdownwardly through the body 18 and the passages 40 and 52 therewithin,this flow of drilling fluid being at a constant velocity and impelled bvmoving downwardly through the string of drill pipe 13. Vhen the member38 has moved upwardly to a suiiicient extent the valve 35 will makeengagement with the upper end thereof and will close the passage 40thereby throwing the ram or hammer 38 into the downwardly moving flow ofdrilling fluid and producing another hammer stroke. At the end of thisconsecutive hammer stroke the valve 35 is released by engagement withthe anvil 64 in the manner previously described and a consecutive upwardstroke of the ram or hammer 38 is then performed and as long as a flowof drilling Huid is continued through the drilling device actuation ofthe reciprocating parts will be maintained.

Each blow of the member 38 produces a penetrating, splitting, cracking,and crushing of the formation constituting the bottom 67 of the well 12by the chopping blades 54 of the chopping cutter 46. The -upper portionor surface structure of the bottom 67 is thereby disintegrated or partlydisintegrated to such an extent that it may be scraped off by thescraping cutter 26 with comparative fa cility.

. The anvil 64 is of removable character so that it may be replaced byanother anvil of greater or lesser height so as to increase or decreasethe length of stroke and consequently the force of the ram or hammerWith reference to Fig. 4, it will be noted that the annular channel 48in the body of the chopping cutter 46 is of much greater vertical widththan the diameter of the steel balls which constitute the retainingmeans 47. Therefore, when no lifting force is eX- erted against thelower end of the chopping cutter' 46 it may drop downwardly from theposition in which it is shown in Fig. 2 to the position in which it isshown .in Fig. 4, the downward movement being limited by the verticalwidth of the annular channel or groove 48.

The import of this construction is that during disengagement of thedrill'bit 11 with the bottom of the well the chopping cutter 46 willrest in the lowered position in which it is shown in Fig. 4 and theparts 38, 42, 44, and 64 which are supported on the upper end of the'chopping cutter 46 will assume a corresponding lowered position in whichthe upper end of the member 38 will be downwardly withdrawn from thevalve 35 so that there will be no possibility of the valve closing thepassage 40 of the member 38 and thereby causing reciprocation of themember 38 during the raising or lowering of the drilling device within awell.

This expedient makes it possible to circulate drilling iiuid through thedrill pipe and the drill bit 11 during the raising and lowering of thedrilling device'without reciprocating the hammering mechanism of thedrilling device. As soon as the bit 11 strikes bottom and the choppingcutter 46 is forced upwardly relative to the body 18 into the positionin which it is shown in Fig. Q, reciprocating .action of the member 38will immediately start and on rotation of the drill hit 11 a combinedscraping and chopping drilling effect will be produced. f i

In Fig. 7 I show the lower portion of a tubular member 8() forming partof a bit body 18, having reciprocating mechanism therein of thecharacter shown in Figs. 2 to 4.

In the lower extremity of the tubular member a Single cutter 81 issecured. This cutter has a body 82 extending within the tubular member80 and a plurality of blades 83. By use of retaining means 84 the cutter81 is secured in vertically movable relationship to the tubular member80 so that by use of the Ihammering mechanism contained in the upperportion of the tubular member 80 the cut. ter 81 may be driven againstor into the bottom formation of a well in an intermittent orreciprocating manner. If desired, the single vertically reciprocablecutter 81 may by interengaging means Such as a key and slot be rotatedby the tubular member 80 whereby a scraping and chopping action may beobtained by the use of a single cutter instead of a combination ofscraping and chopping cutters, as shown in Figs. 2 to 4.

Although I have shown the preferred form of valve mechanism in Figs. 2to 4 of the drawings, other valve mechanisms may be emplo ed toaccomplish automatic reciprocation ofy a hammer member. As shown in Fig.8 a valve 85 may be mounted on a valve stem 86 which projects downwardlythrough a passage 87 in a hammer or ram 88, it being understood that thelower end of the stem 86 engages a stop when the member 88 reaches thelower extremity of its hammer stroke and is thereby released fromclosure position relative to the upper end of the passage 87. y

In this form of valve mechanism the valve has no upwardly extending stemand is lifted into raised position relative to the member 88 asindicated by dotted lines 90, by a spring 91 situated in a recess orcounterbore 92 in the upper end of the member 88.

' lVhen the valve 85 is in the raised -position indicated by the dotted.line the member 88 will be moved upwardly by a lifting spring 93 so thatthe valve 85 will move t0- ward an end member 94 secured in the upperend of the tube 95 of the drilling mechanism. Upward movement of thehammer or ram 88 will then continue until the valve 85 is again closedagainst the upper end of the member 88 and a hammer stroke of themechanism` essentially of a drill body having a passage or openinthereof consis mg of an upper cable and drilling fluid passage 101 and alower chamber 102 ,which is open at its lower end as shown. Supported inthe lower end 103 of the body 100 is a bit body 104 having cuttingblades 105 thereon. The body 104 has a shank 106 which extends upwardlywithin the lower end 103 and is secured for limited vertical movementrelative to the bit body 100 by a plurality of retaining members shownas balls 107 which rest in a groove 108 in the cylindrical wall of thelower end 103 and in a vertically widened groove 110 in the shank 106,these balls being placed in operative positions in the grooves 108 and110 through an opening 111 which is subsequently closed by a plug 112.

For lthe purpose of imparting rotation to the cutter member 104 from thedrill body 100 interengaging or key means 113 may be employed as shownin Fig. 10. lVithin the axial chamber 102 a tubular hammer 114 is placedand a cable which extends through the passage 101 is connected to theupper end of the hammer 114 by means of a suitable yoke or attachmentmeans 116. Water, mud, or drilling Huid in accordance with the rotarymethod of well drilling is pumped downwardly through the drill body 100from from one end to the. otherl the drill pipe to which the body 100 isse cured by a threaded member 117, this drilling fluid passingdownwardly through the passage 101 as indicated by arrows 118, throughthe axial opening of the hammer 114, as indicated by arrows 121, anddischarging from the lower end of the drilling device through openings122 in the cutter member 104 as indicated by arrows 123.

During rotation of the drill body 100 and the cutter member 104 securedto the lower end thereof, and with the cutter member 104 in engagementwith the bottom ofthe hole being drilled, the hammer 114 is raisedwithin the chamber 102 by an upward pull on the cable 115 accomplishedby suitable reciprocating means at the upper end of the drill pipe. Whenthe hammer 114 has been raised a predetermined distance the cable isreleased so as to allow the hammer 114 to fall within the chamber 102into engagement with the upper end of the shank 106 of the cutter member104, thus striking the cutter member 104 and driving the cutting membersor blades 105 thereof into the formation being drilled. The hammer 114,although of considerable weight so as to lproduce a heavy blow onfalling, may be also assisted in its downward movement by friction ofthe drilling fluid which passes through the passage 120 of the hammer114 at relatively high velocity.

In this form of the invention the hammer means is principallymechanically operated but is assisted in its downward movement byhdraulic means consisting of the drillin uid, `as previously described.By suitab e reciprocation of thecable 115 a desired reciprocation orhammer action of the hammer 114 is accomplished,

The form of my invention shown. in Figs. 11 and 12 includes a body 130having a cutter member 131 secured in its lower end in verticallyreciprocable relationship as described relative to Fig. 9. A hammer 132is provided in the chamber 133 of the drilling device, which hammer-issimilar to the hammer 114 but differs therefrom by the use of a valveseat 134 at the upper end of its aXial opening 135 and a valve member136 secured to the lower end of a cable 137 which. projects upwardlythrough a passage 138 to a cable reciprocating mechanism. The valvemember 136 has a limited vertical movement relative to the hammer 132and is contained in a yoke or gauge 140 which is secured to the upperend of, and forms part of the hammer 132. This gauge 140 has aconcentric sleeve 141 through which the cable 137 passes intoengagement'with the valve 136. The sleeve or guide for the cable issupported in the gauge structure 140 by radial webs 142 which vprojectinwardly from the'annular wall 143 of the gauge, the lower port-ions 144of these webs serving as guides for the valve member 136. When the cable137 is pulled upwardly the valve member 136 is raised from the seat 134into engagement with the lower end of the guide sleeve 141. Bycontinuing the upward movement of the `cable 137, the valve member`136may be employed to lift the hammer 132 into raised ,position in thechamber 133.

During the raising of the hammer 132 as shown in Fig. 11 drilling luidpasses downwardly through the gauge 140 as indicated by arrows 145,through the axial passage 135, through an opening 146 in the cuttermember 131 and is discharged through orifices 147 as indicated by anarrow 148. When by use ofthe cable 137 the hammer 132 is raised to theupper end of its-stroke, the cable 137 is released and the valve member136 is thereupon allowed to drop into engagement with the valve seat134, closing the upper end of the axial passage 135 of the hammer 132 soas to have the effect of throwing the hammer 132 into the stream ofdrilling fluid which is traveling downwardly through the body 130, andresultingv in the hammer 132 being carried forcibly into hammer-blowengagement with the upper end of t-he cutter member 131.

In this form of the invention the hammer is raised mechanically and ishydraulically actuated through its downward stroke. By properreciprocation of the cable 137 consecutive actuations of the hammer 132may be accomplished.

In Figs. 13 and 14 I show an embodiment of my invention in which ahammer 150 is moved both upwardly and downwardly by hydraulic action andin which a valve 151 controlled by a cable 152 is employed to controlthe hydraulic action. The hammer 150 has an upper tubular portion 153 ofrelatively small diameter and a lower cylindrical body portion 154 ofrelatively large diameter. The upper portion 153 slides through packingmeans 1 55 carried in the drill body 156, and packing means 157 isprovided on the head 154 for engagement with the inner surface of thecylindrical wall 158 of the drill body 156, there being openings 160through the upper portion of the wall 158, these openings 160 beingsituated immediately below the packing means 155.

When the cable 152 is drawn upwardly so A as to raise-the valve 151 froma cooperating seat 162 in the upper end of the hammer 150 drilling fluidunder pressure tio-ws downwardly through the axial opening 163 of thehammer 150, as indicated by arrows 164, into the space 165 below thehammer 150. The drilling Huid issues through discharge openings 166 i'ua cutter member 167 at a rate of iow which is controlled by the size ofan opening 168 in the upper end of the cutter member 167. This opening168 is of such size that the iluid pressure within the chamber 165acting against the relatively large lower end of the hammer 150 will besuiiicient to overcome the pressure of fluid acting on the relativelysmall upper end of the hammer in downward direction thereby causing thehammer 150 to move upwardly into raised position within the drill body156.

During the upward movement of the hammer 150 fluid accumulated in theannular space 170 below the packing means 155 is forced outwardly intothe well through openings 160. When the hammer 150 is in a raisedposition closing of the valve 151 relative to the valve seat 162 isaccomplished by lowering the cable 152, and immediately upon closing ofthis valve 151 the downwardly moving drilling fluid actuates the hammerdownwardly into engagement with the cutter member 167. The subsequentraising of the valve 151 from engagement with the valve seat 162 byraising the cable 152, releases the fluid pressure in the chamber 172.above the packing means 155 and permits the drilling hammer member 150whereby to produce consecutive hammer blows for the purpose of drivingthe rotating or non-rotating cutter into the earth formation forming thebottom of the well being drilled.

The diameters of the upper and lower ends of the hammer member 150 areproportioned relative to the flow retarding effect of the opening 168 toaccomplish the desired pressures on the upper and lower ends of thehammer member 150 when the valve 151 is opened and closed to accomplishhydraulically the raising and lowering of the hammer, substantially aspreviously described.

In the forms of my invention shown in Figs. 9 to 14 inclusive the hammermeans is controlled from the surface of the ground; and for completingthe disclosure of a complete operative means, I show the surfaceapparatus in Fig. 17. The cable 115 or 152 may have a rod 210 secured tothe upper end, whlch extends through a stufling box 211 of a swivel 212.The rod and cable connected thereto are reciprocated by a beam 214.

The form of my invention shown in Figs. 15 and 16 employs the principlesof hydraulic reciprocation disclosed relative to Figs. 18 and 14, but inthis last form of the invention the cable actuated valve mechanism isreplaced by an automatic valve mechanism 180 consistlng of a valve bodyproper 181 adapted to engage the valve scat 182 at the upper end of theaxial passage 183 of a hydraulically reciprocated hammer 184, and aspring 185 which exerts a continuous pressure tending to raise the valve181 from the seat 182. lVhen the valve 181 is inraised or open positionrelative to the seat 182, the pressure exerted in the lower chamber 186and against the relatively large lower end 187 of the hammer 184, beinggreater than the pressure exerted against the relatively small upper end188 of the hammer 184, produces an upward movement of the hammer,carrying the valve member 181 and the upper end 188 into the respectivepositions indicated by dotted lines 190 and 191, at which time thespider arms or guide members 192 engage the plug or body 193 forming theupper end of the drilling device so that further upward movement of thevalve 181 is thereby prevented and so that the continued upward movementof the hammer member 184 will carry the valve seat 182 intoengagementwith the valve 181. Upon closing of the valve 181, the fluidflowing downwardly into the upper chamber 194 will cause the hammer 184to be forced downwardly at relatively high velocity and underconsiderable pressure, the pressure of the fluid in the chamber 194maintaining the valve 181 in closed position relative to the seat 182,as shown in full lines in Fi 15.

When t e hammer member 184 reaches a point near engagement with a cuttermember 195 reciprocally held in the end of the drilling device, such asshown in full lines in Fig. 15, the spider arms 192 of the valve 181engage in an annular shoulder 196 s0 that further downward movement ofthe valve 181 is prevented thereby. The hammer member 184 is carried bymomentum into engagement with the cutter member 195 and the "alve seat182 is withdrawn from engagement with the valve 181, the spring 185 thenholding the valve 181 in open position, whereupon the drilling fluidwill flow through the axial passage 183 of the hammer member into thelower chamber 186, where the pressure there will operate to lift thehammer member through a return stroke.

In this embodiment of the invention an opening 197 in the cutter member195 is so proportioned relative to the areas of the upper and lower endsof the hammer member 184 that the pressure required for raising thchammer member 184 will be produced in the chamber 186 when the valve 181is open. The automatic opening and closing of the valve member 181 atthe respective ends of the downward and upward movements of the hammermember 184 produces a continuous reciprocation and causes the hammermember 184 to strike consecutive hammer blows on the cutter member 195.

In the disclosure the invention is shown mechanically and hydraulicallyactuated and fully hydraulically actuated. From this it will beperceived that the invention includes not only a drilling device havinga hammer hydraulically actuated by the drilling fluid but also adrilling device in which a hammer is operated partly by springs andhydraulic action or by fully mechanical means, such as a cable extendingto the derrick of the well drilling equipment.

Although I have` shown simple and practical forms of my invention, it isrecognized that parts or elements thereof may be replaced by other partsor elements by which substantially identical result-s may beaccomplished; therefore, it is to be understood that my invention is notlimited to the details of the foregoingdisclosure but should be accordedthe full scope of the following claims.

I claim as my invention:

1. A drilling device of the character described, including: a bodyadapted to be secured to the lower end of a string of drill pipe, saidbody having passage means for conducting a flow of drilling mud fromsaid drill pipe to the lower portion thereof; a vertically reciprocablecutter mechanism at the lower end of said body; a reciprocable member insaid body adapted to engage and disengage said cutter mechanism, saidmember having a vertically directed opening therethrough, through whichthe flow of drilling mud passes; means foryieldably forcing said toperiodically close said opening through said member so as to cause saidreciprocable member to move downwardly with the flow of drilling mudthrough said body and forcibly engage said cutter' mechanism.

2. A drilling device of the character described, including: a bodyadapted to be secured to the lower end of a string of drill pipe, saidbody having passage means for conducting a How of drilling mud from saiddrill pipe to the lower portion thereof; a vertically reciprocablecutter mechanism at the lower end of said body; a reciprocable member insaid body adapted to engage said cutter mechanism, said member khaving a`vertically directed opening therethrough,

through which the flow of drilling mud passes; means for yieldablyforcing said member upwardly; a valve adapted to seat against the upperportion of said member so as -to close said opening; an upper stop forsaid valve for holding said valve in position to engage said member atthe upper end of the movement of said member in saidbody; means foryieldably forcing said valve toward said upper stop; and a. lower stopfor engaging said valve and moving it from closing position relative tosaid opening when said member approaches the lower end of its movementin said body.

3. A drilling device of the character described, including: a tubularbody adapted for attachment to the lower end .of a drill pipe; a cutterelement at the lower end of said body, having a part projecting withinsaid body; a hammer member vertically movable in said body, said hammermember having an opening therethrough for passage of drilling fluid; avalve for closing the upper end of said opening; an upper stem extendingupwardly from said valve; a hollow member projecting downwardly withinsaid body and around said upper stem, said hollow member providing astop for limiting the upward movement of said valve; means engaging saidstem for yieldably forcing said valve upwardly; a spring for moving saidhammer member upwardly into engagement with said valve when said valveis in raised position, such engagement causing said hammer member tomove downwardly with the iow of drilling fluid through said body soas tostrike said part of said cutter element; and a lower valve stemextending within said passage of said hammer member, for releasing saidvalve as said hanmier member approaches said part of said cutterelement.

4. A drilling device of the character described, including: a tubularbody adapted for attachment to the lower end of a drill pipe; a cutterelement at the lower end of said body, having a part projecting withinsaid body; a hammer member vertically movable in said body, said hammermember hav- Iing an openingtherethrough for passage of drilling fluid; avalve for closing the upper end of said opening; an upper stem extendingupwardly from said valve; a hollow member projecting downwardly withinsaid body and around said upper stem, said hollow member providing astop for limiting the upward movement of said valve; means engaging saidstem for yieldably forcing said valve upwardly; a spring for moving saidhammer member upwardly into engagement with said valve when said valveis in raised position, such engagement causing said hammer member tomove downwardly with the flow of drilling fluid through said body so asto strike said part of said cutter element; a lower valve stem extendingdownwardly from said valve and through said passage of said hammermember; and a lower stop adapted to be engaged by said lower valve stemwhereby to release said valve as said hammer member approaches saidcutter element.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 17th day of April, 1930.

JOHN A. ZUBLIN.

sus

